Morais, who leads Ally's consumer and commercial banking divisions, was seen as a potential candidate to replace outgoing CEO Jeffrey Brown. She and Brown have both been at Ally since its early days, when it was spun out of General Motors Acceptance Corp. and launched a low-fee digital deposit-taking arm.

Ally has since grown to more than $135 billion in retail deposits. In 2021, Morais pioneered Ally's elimination of overdraft fees, the effects of which would ripple across the banking industry, as competitors scrapped or reduced their reliance on the fees.

"From launching the first all-digital bank during the Great Recession — recognizing the world didn't need another bank, it needed a better one — to being the first to eliminate overdraft fees, Di's vision and leadership led the entire industry to a more customer-centric focus on what's right," an Ally spokesperson said in a statement.

Morais plans to stay on as Ally's president of consumer and commercial banking until July 1. The company disclosed her planned departure Tuesday in a filing to investors, which said that Morais "has been considering retirement from the Company to pursue new opportunities."

Brown, Ally's longtime CEO, is staying at Ally until Jan. 31 at the latest. The Ally filing said that Morais is staying on to provide "seamless support to the new CEO." 

"We have the utmost confidence these powerful, customer-centric businesses, headed by experienced and strong leaders, will maintain their momentum," the Ally spokesperson said.

Ally declined to share any updates on the search for a new CEO or whether its board is considering any internal candidates for the post.

"The Board has engaged a leading global executive search firm to help ensure we bring on the best possible candidate," the spokesperson said. "We will not speculate on the candidates."

Morais' remit at Ally is broad. She leads the company's deposit platform, its investment arm, its mortgage lending business, its personal lending arm, its recent expansion into credit cards and its Community Reinvestment Act program. She also leads Ally's commercial banking division, where the bank works with middle-market companies.

Before joining Ally in 2008, Morais spent 12 years in Bank of America's consumer unit and nine years in Citigroup's credit card division.

American Banker ranked Morais No. 7 on its Most Powerful Women in Banking list this year, citing Ally's success in gathering deposits and its more recent expansions into wealth management and credit cards.

Ally bought the credit card issuer Fair Square Financial in late 2021. Between when the sale was announced and the third quarter of this year, Ally grew its card loan balances from less than $800 million to $1.9 billion.

"We're seeing consumers adopting that additional service, so we think that's going to be a growth engine for Ally as we move into the future," Morais told American Banker earlier this year. "It's just another piece of the tapestry, but so far we're extremely pleased with how the business has performed."